The invention is useful in machine knitting on a weft knitting machine having independently operable needles disposed in at least two needle beds, for example, a flat V-bed machine producing a mainly double jersey structure. In such machines, the width of the knitted fabric is restricted by the maximum number of needles available for forming a course across the machine bed.
Knitted three-dimensional fabric structures for covering three-dimensional objects are produced from two-dimensional material and have in the past been produced by weaving or knitting shaped parts and panels and sewing them together.
More recently, it has been found possible to knit one-piece upholstery fabric, which removes the need for sewing portions together, and has the desired shape to serve as covers for the base and back cushions for vehicle seats; see, for example, British Patent 2,223,034. A problem that has arisen with the continuous knitting of three-dimensional fabric structures is that it has hitherto been impossible to knit satisfactory joint edges where the angle between the edges-to-be-joined in the two-dimensional form exceeds 135.degree., and generally the maximum angle for continuous knitting together of edges should not exceed an angle of 90.degree. depending upon the application. Generally, the larger the angle between the edges-to-be-joined, the poorer the appearance and strength of the joint. British Patent Application GB-A-2,223,036 discusses in detail the problems associated with continuous knitting of edges-to-be-joined having large angles therebetween.